MMA to learn how to deal with truly resisting opponent + Krav to learn street tactics, tricks and avereness.Well, if youre really good at BJJ, you will be dangerous, like you will with judo etc. Do judo 5 times a week for 20 years and you'll be a monster and ragdoll almost anyone.
but in my view, i think you want to compare volume of training to effectiveness, thats when it gets interesting. here i believe regular boxing, strength training (atleast until you've taken out the easy gains within a year or two) and krav maga ranks high.
im not willing to move into the gym to learn self defense. If youre like me, in our 40s and willing to spend 2-4 hours a week learning something for self defense, what should that something be?
Or start with MMA, and later add Krav.